esnext.async-iterator.take.js 1017 Bytes
'use strict';
// https://github.com/tc39/proposal-iterator-helpers
var $ = require('../internals/export');
var anObject = require('../internals/an-object');
var toPositiveInteger = require('../internals/to-positive-integer');
var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');

var AsyncIteratorProxy = createAsyncIteratorProxy(function (arg, Promise) {
  var iterator = this.iterator;
  var returnMethod, result;
  if (!this.remaining--) {
    result = { done: true, value: undefined };
    this.done = true;
    returnMethod = iterator['return'];
    if (returnMethod !== undefined) {
      return Promise.resolve(returnMethod.call(iterator)).then(function () {
        return result;
      });
    }
    return result;
  } return this.next.call(iterator, arg);
});

$({ target: 'AsyncIterator', proto: true, real: true }, {
  take: function take(limit) {
    return new AsyncIteratorProxy({
      iterator: anObject(this),
      remaining: toPositiveInteger(limit)
    });
  }
});